Electronic distributor



0t.\12;1937. w.G. HflNcHi 2,095,929 u ELECTRONIC DISTRIBUTOR `originalFiled Dec. 4, 1935 ATTORNEY Patented Oct. 12, 1937 UNI-TED STATES ELECTRONIC DISTRIBUTOR William G. H. Finch, New York, N. Y.

Original application December i, 1935, Serial No. 52,871, now Patent No. 2,057,773. Qivided and this application October 8, 1936, Serial No.

6 Claims.

My invention relates to electronic distributors useful for signalling systems, and more particularly relates to the application of an electron beam distributor for high speed printing telegraph.

This invention is a division of the parent application Serial No. 52,871 filed December 4, 1935 which matured into Patent No. 2,057,773 onOctober 20, 1936.

Modern high speed printing telegraph systems operate with a Baudot or ve unit code. A continuous tape is successively punched with predetermined combinations of holes for the characters. It is the practice to pass thev tape through apparatus having mechanical feelers which in turn operate contactors connected to contact plates on a mechanical distributor. The mechanical distributor, as is well known in the telegraphy art, comprises a rotating arm for successively contacting the contact plates to transmit coded impulses in succession. The operation of mechanical distributors materially limitsthe speed of transmission of printing telegraph signals.

It is accordingly themain object of my present invention to eliminate the mechanical distributor and substitute therefor an electronic distributor. The electron beam of a cathode ray tube is caused to scan a plurality of metallic plates or ytargets corresponding to the individual contacts of a mechanical distributor. 'I'he substitution of an inertialess selector for the mechanical selector in a distributor makes possible accurate transmission of telegraphy signals at much higher speeds than heretofore possible. A receiver is arranged having an electronic distributor similar to that of the transmitter winch selects the transmitted code signals to operate standard telegraph printing apparatus.

40 Although the mechanical distributor .for the printing telegraph receiver of my present invention is most suited for speeding up the operation of translation of the signals, it is evident that it may similarly be employed with a transmitter in- 45 volving mechanical selection of the signal impulses corresponding to the signal groups set in the punched signal tape. A mechanical distributing system at the transmitter end to produce the successive coded signal impulsescorre- 50 spending to the B-unitcharacter code plus one unit for the printing and resetting operation will naturally slow up the operation of the system as a Whole. However, the electronic distributor corresponding to my present invention, when used at the receiver, will avoid the sparking, wear and other diiliculties that the mechanical distributors inherently are subjected to, to improve the operation and maintenance of the printing telegraph receiving station. However, I prefer to 60 employ the electronic distributor of my invenchanical distributor in printing telegraphy systems. l Still another object of my invention is to provide a novel means for synchronizing the operation of transmitter and receiver distributors in signalling systems. y A further object of my invention is'to provide novel methods ofand means for high speedV` transmission of coded signalssuccessively punched in a perforated message tape.

These and other objects of my invention will become apparent in the following description in connection with the drawing, in whichzl Figure 1 is a schematic 'illustration of a. transmitting telegraphy system employing an electronic distributor according to my invention.

Figure 2 is a schematic illustration of a re ceiver for translating the printing" telegraphy signals transmitted according to Figure 1.

Although the electronic printing telegraph re- ,ceiver may be employed with different types of transmitters an electronic transmitter is preferable to maintain the highest over-all speed of transmission. The transmitter is illustrated in Figure 1. The electron beam I0 is produced in a highly evacuated vessel II. The generation of the electron beam is familiar to those skilled in the electronic art and is schematically shown. The cathode I2 is heated by the heater I3 which is connected to suitable battery supply. The ilrst anode I4 concentrates the emitted electrons into an electron beam. The high voltage anode I5 accelerates the electrons of the beam IIJ which passes between the electrostatic deecting plates I6, I1, I8 and I9 and on to the opposite end 20 of the Vessel II. v

A high voltage direct current potential source 2I supplies the operating potentials for the electrodes of the cathode ray tube II. A potentiometer 22 is connected across the battery 2|. The second or high voltage anode I5 is connected t'o the positive side, 23 of the potentiometer 22 which point is connected to ground in my preferred embodiment. The first anode I 4 is connected to a suitable intermediate potential by tap 24. The control grid 25 is negatively biased with respect to the cathode I2 by a suitable tap 26 of the potentiometer 22. Deilecting plates I6 and I9 s are connected to the grounded .high potential point 23 to assume the same potential as the anode l5. The plates I1 and I9 are connected to ground through high resistances 21 and 29 so that the electrostatic defiecting plates and the `anode I5 have a common' static potential which is at ground potential, an operating expedient commonly employed.

On the back face 29 of the tube II, I arrange a plurality of metallic plates or targets 29 within the tube. As illustrated in Figure l, these plates 29 are spaced around a circle within the tube II and have connections projecting through the tube at pointsli. Five of the metallic electrodes 29 are connected to corresponding contactors 3l of a selector mechanism.' 32. In modern printing telegraphy, a message tape is employed which has a succession of holes punched according to a predetermined code. The commonly used Baudot code, for example, employs combinations of five units to correspond to individual letters or symbols. The punched tape is passed through a. selector mechanism which has five feelers which coact with the tape and operate contactors 3| as is well known in the art. I have schematically illustrated such a selector mechanism at 32.

The contacts of the contactors 3| are connected in parallel across the input circuit 33 of a thermionic amplifier stage 34. The output 35 of the amplifier 34 is connected to a modulator 36 for modulating s. radio frequency carrier produced by the radio frequency oscillator '31 connected to the radio frequency amplier 39 to be transmitted for radio transmission by the antenna. 39.

A local oscillator 40 is connected to the electrostatic deilecting plates I1 and I9 through a rotator circuit 4I comprising a condenser 42 and resistance 43 connected as shown. The impedance of the condenser 42 is adjusted to be substantially equal to the resistance 43 at the frequency of the local oscillator 40. The electron beam III will be moved in a circular path as is well known in the art. 'I'he diameter of this circular path 44 at the end 2li of the tube I I depends upon the voltage output of the oscillator 40 which is adjusted so that the diameter of the path 44 coincides with the mean diameter of the circularly arranged plates 29. There is thus provided` means for successively scanning the electrodes 29 at a predetermined rate.

When the electron beam I9 impinges on a target 29, the electrons will be conducted to ground actuated by its selector feeler, but connects to the lower contact. However, if a'feeler of the selector mechanism 32 at that time projects through a hole in the perforated tape, an arm of the corresponding contactor, for example, IIa, will be moved to connect to its upper contact on the corresponding' target 29a will be conductively connected to the grid 43 of the thermionic amplifier 34. The electrons of the beam Ill are attached to ground since the high potential side of its accelerating battery source 2i is connected to ground. The electrons of the beam IIl accordingly pass to ground through the input circuit or grid resistor 33. The electrons flowing through the grid resistor 33 produce a potential change upon the grid 46. A corresponding impulse is transmitted through the amplifier 34 to its output 33. Accordingly, while the electron beam I9 is passing over an electrode 29 having its cor- 75 responding contactor 3l actuated by a selector through its corresponding contactor 3l if itis not point 45 and the electrons of beam I0 impinging feeler projecting into a hole in the perforated tape, electrons will be conducted to the input circuit 33 of the amplifier 34 and produce a pulse or signal therethrough. This pulse or signal is introduced to the modulator 39 for radio transmission as described.

The operation of the electronic distributor according to my invention therefore is to cause an electron beam III to successively scan a plurality of metallic target electrodes 29 arranged at the far end of the evacuated envelope II. The electrodes 29 are connected to individual contactors 3i of a selector mechanism 32 of a perforated tape telegraphy system. Each contactor 3l and its corresponding electrode 29 correspond to a predetermined component of the five unit code of the perforated tape. With each symbol group punched in the tape, a corresponding arrangement of contactors 3I will be actuated to their upper contacts 'during the transmission of the code group. The frequency of the oscillator 40 is adjusted so that it successively scans all the electrodes 29 once for each code group advanced through the selector mechanism 32,. Each contactor 3I actuated by a holein the perforated tape conductively connects its corresponding electrode 29 to the grid V43 of. the amplier 34, and a signal pulse will be produced by the ampliiler 34 when the electron beam I3 passes over this target 29. Accordingly, a succession of signal vpulses is transmitted corresponding to the code group on the perforated tape being presented to the mechanical feelers in the selector mechanism.

The selecting mechanism Afeeds the perforated tape at a predetermined rate in accordance with the frequency of scanning of the electrodes 29 and each code group is retained by the selector pins during the execution oi' each cycle of scanning. The electron beamwill therefore be conductively connected to the grid 43 of the amplier 34 as it successively scans the electrodes 29 in accordance with the code group being transmitted. The oscillator 49 is connected to the modulator 36 by leds 41. The radio frequency carrier wave which is radiated by antenna 39 is modulated by the signal impulses and by the scanning frequency. The purpose y chronizedwith the scanning movements of the,

electron beam Il over the targets 29. The tape is retained in the selector mechanism during the scanning operation of a code group and is advanced to the nextvcode group at the end of each cycle. 'l'he actuating means for the stepping of the tape through the selector mechanism is preferably van electro-magnetically operated pawl and ratchet arrangement schematically shown as 32a. I provide a sixth target electrode 29h, which is connected directly to the stepping mechanism 32a. A signal amplifier is included in the electro-magnetic unit 32a. to sufficiently amplify the impulse to operate the mechanical stepping means. The electrode 29h sets off the five signal targets 29 into one group. At the end of a code group transmission, therefore, the

electrode 29h is impinged by beam I0 and the electromagnetically operated stepping mechanism automatically advances the message tape to the next code group to be transmitted. The cycle is then repeated. The rate of transmission of the code groups is accordingly predetermined The target 29h is also connected to the input pulses will bring the electron beam 66 into proper by adjusting `the frequency of the oscillator 40, 61. Accordingly, the electron beam 66 moves in the numberV of groups transmitted per second the circular path at a predeterminedrate being equal to the generated cycles per second equal to the rate oi beam IU at the transmitter. of the oscillator 49. In the embodiment of Figure 2, the signal im` circuit 33 of the signal impulse amplifier 34 focus upon the electrodes 61. but during no through a unidirectional impedance device 48. signal" the negative potential of the grid will 46 may be a buier stage of thermionlc ampliiicabe such as to throttle the`bem 66 to prevent its tion, or a rectiiler. A unidirectional impedance reaching the electrode 61. When the electron 1o 49 is yused to transmit an electron beam I0 imbeam 66 impinges upon `a target 61, a pulse is 10v pulse at target 29h to the signal ampliiler 34. introduced to the input of the correslfioncling...

but to prevent any signal impulses from other ampliiier 69. The production of the pulse by targets from reaching the'stepping amplifier 32a. theelectron beam 66 at the ampliiler 69 input Illl'he stepping mechanism 32a will therefore be ls the same as the production oi lthe signal im- 15 actuated only by the impulses on target 29h for pulse introduced at the grid 46 of the ampliiier 15 ing impulse. The function of. the printing The phase ofthe alternating current scanning 20 tenna 49 is connected to the radio receiver 46 targets 61 in synchronization with the corre- 25 the oscillator 4 6. The output of thefiilter 69 is the electrode 29a, the receiver electron beam '66 30 I nected to ground potential. The second anodel the electronic distributor accordin to my inven- 35 of the potentiometer 69. Resistors 63 and 64 coded perforatlns in the passing there- 4p or Figure 1. An electronic beam 99 is produced mieter. A "printing impulse is transmitted at 4,5

`m amplifiers 69 at the outputs of which are conprinting impulse relay 16h. 'I'he printer relay 50 proper action thereof. 'I'he impression of the 64 of Figure 1 described hereinabove. The amimpulse of target 29h upon the signal amplifier pliflers 69 are made sulilciently sensitive to suit- 34 is to transrnlt, at the end oi' each cycle, an ably energize the corresponding relays 10 for impulse to be utilized at the receiver as a printactuating the local printing mechanism.

impulse will be described hereinafter in consignal iiltered at 66 and introduced to the amnection with the receiver printing mechanism. pliiler 6I is adjusted by well known phase shift- In Figure 2, is illustrated a receiver system ing means, schematically indicated at 16,tocause employing an electronic distributor. Theanthe electron beam 66 to pass over predetermined which detects and amplies the telegraphy sigsponding targets at the transmitter in order to nals. A filter 69 is connected to the audio circuit properly maintain the code combinations at the o1' the receiver 49 and is tuned to pass the scanprinting mechanism. Accordingly, when the ning frequency generated at the transmitter by electron beam I 6 of the transmitter impinges on introduced to an'amplier 6l whichis connected will impinge upon the corresponding electrode to the electro-static deiiecting plates 63 and 64 61a to actuate the printing relay 16a, in proper through the rotator circuit 62. Their corresequence. Once the beam 661s adjusted in proper sponding deilectlng plates 66 and 66 are conphase relation with the transmitted impulses,

61 `is also connected to ground potential as is tion will continue to be in synchronism with the the positive terminal of the'high voltage direct transmitter'and operate to selectively print the current source 66. 4The operating potential of letters or symbols which are selected bythe mechthe ilrstvanode 6| is adjusted with the tap 62 anism 32 of the transmitter according to the `having high resistance. connect the defiecting through,

n Plates 53 and 54t08r011nd- A sixth target .1b is included in the target The receiver electronic distributor 66 .is of group oi the receiver electronic distributor 66,

similar construction to that of the transmitter and corresponds to the target 29h at the transand caused to scan a plurality of metallic electhe end o: each code group as hereinabove'detrodesfor targets 61 arranged in a circular path scribed, corresponding to the target 61h. Acon the back wall 68 of the evacuated envelope. oordingly, an impulse will be impressed through The targets 61 areindividually 4connected to 4target; 61h upon the amplifier .66h t0 actuate u nected relays 16. There are ve relays 19 which 10b may be employed to directly print the char-v arc used t0 Operate 100811 Printing telegraphacter` selected by the other nve rela'ys 16, orl may The rectified unidirectional output of the receiver function to transfer the code group set up to 49 is connected tothe primary of'transformer 1I another group of magnetsor selectors provided the secondary Ofwhich 1s impressed across the in a manner well known in the art.' The relays 55 grid 12, and CathOde 59- The grid 12, bias DO- 10 will thereafter be reset in readiness for the tential is adjusted to a suitable negative @value noxooodo group transmitted;

by the potentiometer 1l connected across the The sognnmg frequency in Vcycles per second grid biaslng battery 14. equal to the rate` of transmission o! code groups `o() The synchronizing frequency impressed aCrOSS -per second. 'I'here is no inertia, mechanical wear,v 60

the electrodes 66 and 54 through the rotator cir- Spalking or dust troubles with'the electronic djs. cuit 52 produces a rotation of the lelectron beam tributor of my invention. AV greatly increased 66. The voltage output of the ampliiler 6| is speed of operation m possible with this system l preferably adjusted to produce a path diameter as compared to the tologmphy systemgwhich use o5 15 of the electron beam 66 about equal to the .mechanical distributors, v 65 ro when a signal impulse is impressed von the to transmitted characters; an electronic' distribmean diameter of the circularly arranged targets I claim: l 61. 'I'he operating potentials oi' the electrodes 1 In a printing telemph system' means for are adjusted 5 that the beam n Wm be P1' 0p' receiving successive groups of coded substantially erly focused t0 imping? Pon the targets 57 uniform intensity signal impulses corresponding grid 12. The bias of the grid 12 is adjusted so utor for said sigilo] impulsos oomprismg means that when no signal impulse 1S transmitted for generating an electron beam, a plurality o! through the transformer 1I, it will be suilltarget electrodes gpacedly arranged in a fixed ciently negative to throttle the electron beam path, means for normally moving said beam at a 66 and prevent it from reaching the electrodes predetermined rate in the region of said target 75 electrode path, and means for selectively impinging said beam upon an individual target electrode in response to a signal impulse; and relay units individuallyuconnected to each of said targets, responsive to the impinging of the beam upon the targets and being capable of being actuated once per code group to select a local printing character corresponding to the transmitted character in accordance with the particular combination of targets impinged by the beam during ,the associated group signal reception.

2. In a printing telegraph system, means for receiving successive groups oi coded substantially uniform intensity signalimpulses corresponding to transmitted characters; an electronic-distributor for said signal impulses comprising means for generating an electron beam, a plurality of target electrodes spacedly arranged in a iixed path, means for normally moving said beam at a predetermined rate in the region of said target electrode path, and means for selectively impinging said beam upon an individual target electrode in response to a signal impulse; and relay units individually connected to each of said targets, responsive to the impinging of the beam upon the targets and being capable of being actuated once per code group to select a local printing character corresponding to the transmitted character in accordance with the particular combination of targets impinged by the beam during the associated group signal reception, one o! said relay units being connected to apredetermined target velectrode and responsive to a cyclic signal impulse for operating the printing and resetting of the local characters between the reception or each successive signal group.

3. In a printing telegraph system, means for receiving successive groups of coded substantially uniform intensity signal impulses corresponding to transmitted characters; an electronic distributor for said signal impulses comprising means for generating an electron beam, a plurality of target electrodes spacedly arranged in a circular path. means for normally moving said beam at a predetermined rate in the region of said target elec- .trode path, means for adjusting the relative phase position of the movement of said beam with respect to said target electrodes, and means for selectively impinging said beam upon an target electrode in response to a signal impulse; and relay units individually connected to each of said targets, responsive to the impinging oi the beam upon the targets and being capable of being actuated once per code group to select a. local printing character corresponding to the transmitted character in accordance with the particular combination of targets impinged by the beam during the associated group signal reception.

4. In a printing telegraph system, means for receiving successive groups of coded substantially uniform intensity signal impulses corresponding to transmitted characters; an electronic distributor for said signal impulses comprising means for generating an electron beam, a plurality of target electrodes spacedly arranged in a iixed path, means for normally moving said beam at a predetermined rate in the region of said target electrode path, means for adjusting the relative phase position of the movement of said beam with respect to said target electrodes, so that a predetermined target is reached by the beam at the end of each signal group reception, and means for selectively impinging said beam upon an individual target electrode in response to a signal impulse; and relay units individually connected to uniform intensity signal individual each of said targets, responsive to the impinging of the beam upon the targets and being capable of being actuated once per code group to select a local printing character corresponding to the transmitted character in accordance with the particular combination of targets impinged by the beam during the associated group signal reception, one of said relay units being connected to said predetermined target electrode and responsive to a cyclic signal impulse for operating the printing and resetting of the local characters between the reception oi each successive signal group.

5. In a printing telegraph system, means for receiving successive groups of coded substantially uniform intensity signal impulses corresponding to transmitted characters; an electronic distributor for said signal impulses comprising means for generating an electron beam, a plurality of target electrodes spacedly arranged in a circular path, means for normally moving said beam at a predetermined rate in the region of said target electrode path, comprising a rotator circuit connected to said distributor and responsive to a received vsynchronizing frequency current, and means for selectively impinging said beam upon 'an individual target electrode in response to a signal impulse comprising an electrode for controlling the focusing of said beam upon saidv target electrodes, connected to the output of said receiving means; and relay units individually connected to each of said targets, responsive to the impinging of the beam upon the targets and being capable o! being ac- .tuated once per code group to select a local printing character corresponding to'the transmitted character in accordance with the particular combination of targets impinged by the beam during the associated group signal reception.

6. In a printing telegraph system, means for receiving successive groups of coded substantially impulses corresponding to transmitted characters; an electronic distributor for said signal impulses comprising means for generating an electron beam, a plurality of target electrodes spacedly arranged in a fixed path, means for normally moving said beam at a predetermined rate in the region of said target electrode path, comprising a rotator circuit connected to said distributor and responsive to a received synchronizing frequency current, means for adjusting the relative phase position of the movement of said beam with respect to said target electrodes. so that a predetermined target is reached by the beam at the end of each signal group reception, and means for selectively impinging said beam upon an individual target electrode in response prising an electrode for controlling the focusing of said beam upon said target electrodes, .connected to the output of said receiving means; and relay units individually connected to each of said targets, responsive to the impinging of the beam upon the targets and being capable of being actuated once per code group to select a local printing character corresponding to the transmitted character in accordance with the particular combination of targets impinged by the beamdurlng the associated group signal reception, one of said relay units being connected to a predetermined target electrode and responsive to a cyclic signal impulse for operating the printing and resetting of the local characters between the reception of each successive signal group.

WILLIAM G. H. FINCH.

to a signal impulse, com.- 

